1. Technical Field
The present invention relates to a flame-retardant resin composition for an aluminum electric wire and an aluminum electric wire using the same.
2. Background Art
As insulator materials for a conventional heat-resistant electric wire for automobiles, there are resin compositions in which a bromine-based flame retardant is added as a flame retardant to an olefin-based resin. In recent years, it has been demanded not to generate a halogen-based gas that causes influence on the human body and corrosion of devices. Therefore, a composition to which magnesium hydroxide is added as a flame retardant instead of the bromine-based flame retardant (a non-halogen composition) has been a main stream.
Moreover, weight saving has been demanded for recent automobile parts and, also as electric wires for automobiles, weight saving has been required. Therefore, there has been proposed an aluminum electric wire in which the conductor is changed from copper (Cu) to aluminum (Al). Since aluminum has a thermal conductivity equal to 60% of that of copper, heat is prone to be accumulated in the inside thereof in the case where aluminum is applied to an electric wire. As a halogen-free insulating material for an insulated electric wire using such aluminum as a conductor, it has been found that, for enhancing flame retardancy, it is best to increase the amount of magnesium hydroxide to be added. In order to dissolve magnesium hydroxide homogeneously in a resin and improve flame retardancy and mechanical properties, there is known a non-halogen flame-retardant resin composition in which a maleic acid-modified resin is blended (for example, see JP-A-2005-314516 and JP-A-2006-225480).